Rinnai Tankless Hot Water Heater - $100 (Blacksburg / Pembroke)

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make / manufacturer: Rinnai
model name / number: R75LSi

Below is an ad I made ans posted in December... the HWH ad expired and TBH I forgot about it. I've taken new photos May 2024 and cut the price by $50. One of the photos show the HWH in a box but plugged in to show it still powers up. Thanks!


This tankless hot water heater has a leaking heat exchanger. If you can use a screwdriver, and wait for parts, you can repair it. I could not wait for parts, so I replaced the whole unit. If you are still interested, read more below:

This is a Rinnai R75LSi. I believe the “i” is for interior install. 190,000 BTU, 7.5GPM. This unit uses Propane. There are conversion kits that allow for natural gas usage, but I don’t know if they available for this model or anything about them, really. Water valves are included. You can't see them from the camera angle, but the wall mount brackets are built in.

This unit was built July 2008 and put in my house either end of 2008 or early 2009. Removed towards the end of October. I’ve owned it the whole time and have cleaned / serviced it regularly.

As stated, the heat exchanger is leaking. It started leaking – like a heavy drip – just as I was finishing servicing the unit. I suspect the sudden pressure of turning the supply water on was the final straw for some part of the heat exchanger. But, it hasn’t been leaking all over the electronics or elsewhere for any period of time. It started leaking as I was standing there, I turned off the water supply, the end.

I talked to Rinnai USA and they do have heat exchangers but they don’t sell direct. They did mention a couple of online supply houses (they specifically mentioned PartsTown) that don’t have it in stock themselves but drop ship from Rinnai. It’s part number 104000032-K or sometimes 104000032K. Blackhawk Supply claims to have it for $450 and PartsTown is $600. Alternatively, you could find the leak and braze it (it’s copper).

There’s a great YT video by That Tankless Guy called “Rinnai heat exchanger removal on a non condensing unit” where he goes through the whole heat exchanger removal process. He performs it on the outdoor mounted version of this model but also has this exact model on hand and points out the few differences. It is a gut job but it’s all just screws and unclipping electrical connectors.

To be honest, if I (we) could have waited it out, I would have gotten the parts and fixed instead of replaced this unit. I’ve taken care of it and it still works fine.

Cash only, As-is, contact via email. I am in Blacksburg a couple of times a week and can meet there. I can also meet in Pembroke or Newport.

post id: 7744485571


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